crutschow:
Well, I might be wrong about it. My experience is limited, so I am still learning.
I use 5v to run my ne555, but will change it to 12v. What I mean by the messy sentence is, that I read, that a power MOSFET will require up to 1 Amp to be fully saturated at high frequency. The ne555 should be able to push around 200ma which I thought as a limit. My hope was to reach a PWM frequency between 100khz - 1Mhz, but have no idea if that is considered a high or low frequency? The ne555 might be my limit here? The best I have seen on my 555 is around 300Khz so far, but havent got a clue if its useful at that frequency.
Earlier I used a BD139 power NPN which seemed to not open completely with 2-4v at the output pin of my ne555, which made me try the logic gate transistor instead. The logic gate transistor gave me some other issues, already solved, thanks to you.